CVE-2026-4740 PUBLISHED

Rhacm: open cluster management (ocm): cross-cluster privilege escalation via improper kubernetes client certificate renewal validation

Assigner: redhat
Reserved: 24.03.2026 Published: 07.04.2026 Updated: 07.04.2026

A flaw was found in Open Cluster Management (OCM), the technology underlying Red Hat Advanced Cluster Management (ACM). Improper validation of Kubernetes client certificate renewal allows a managed cluster administrator to forge a client certificate that can be approved by the OCM controller. This enables cross-cluster privilege escalation and may allow an attacker to gain control over other managed clusters, including the hub cluster.

Metrics

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS Score: 8.2

Product Status

Vendor Red Hat
Product Multicluster Engine for Kubernetes
Versions Default: affected
Vendor Red Hat
Product Multicluster Engine for Kubernetes
Versions Default: affected

Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Credits

  • Red Hat would like to thank Arnaud FEVRIER (Orange) for reporting this issue.

References

Problem Types

  • Improper Certificate Validation CWE